Why is preview with MSP6.5 so slow?

[Patrick]

I've recently updated to MSP6.5 from 6.0 and although there are some improvements, I'm really unhappy with how long it takes to preview video with it. To be more precise, I'm choked because of how long it takes to preview the audio.

I capture DV using MSP's program. When editing with version 6.0, I was able to preview type 1 DV and choose PCM audio. This allowed the preview files to be created very quickly. With version 6.5, the option to choose PCM audio when previewing type 1 DV has been eliminated. I'm now forced to choose DV Audio - NTSC and it takes so long to render these audio files.

Am I missing something here?

[Jerry Jones]

Patrick,

Why do you say there's no longer an option to use PCM audio with MediaStudio 6.5?

That puzzles me because I'm using version 6.5 at work with a Canopus DV Raptor board and my project setting is... you guessed it... PCM audio.

Are you talking about OHCI boards?

JJ

[Jerry Jones]

Also...

1. How much ram do you have?
2. What's your processor speed?
3. Which OS are you using?

[Jerry Jones]

I'm also puzzled by your impression that PCM audio "renders faster" than DV Audio.

I don't get that at all because it's the opposite of what I've experienced.

First, my previews are instant with the Instant Playback feature.

There's no waiting.

Second, it's the Raptor's PCM audio that requires re-rendering.

DV Audio with OHCI cards... in my experience... requires absolutely no re-rendering... it plays back instantly.

Jerry

[Patrick]

I'm confused...

Jerry, this has surprised me as well. Regarding the specs you asked about:

1) At one time I had 1024 Mbs of RAM, but have reduced it to 512 Mbs because it was overkill.
2) The processor is a Celeron 900 overclocked to 1116 MHz.
3) I'm running Win98SE.

Using MSP and a Pyro DV card, it appears that the video is captured as type 1 DV. In Project Settings, when I select DV Audio-NTSC, the audio seems to have to be rendered before previewing the video. None of the video is rendered (except for transitions, titles, etc), but the audio is rendered after the scrubber goes across the timeline. If I simply "kill" the audio on the left hand side of the audio time line(s), no rendering occurs and the preview comes up MUCH quicker.

In version 6.5 one can choose PCM audio only when using type 2 DV files. However, version 6.0 allowed the user to choose PCM audio with type 1 or 2 DV. Am I the only one to have found that this made for much shorter rendering times when previewing? Obviously I didn't choose PCM audio when outputting and recording on my Sony TRV900 camcorder, but for previewing it was great.

I haven't had much time to try everything out with 6.5, but I'm puzzled by your reference to "Instant Playback". I've not seen evidence of this. It seems the same (or slower) than 6.0. I'd be interested to hear if I'm doing something wrong.

[Patrick]

Must be sleep deprivation...

Umm... Ok, I feel kinda dumb right now. I just discovered where the Instant Play command is.

I'm still puzzled by my earlier observations, but I'll have to try out this new function and report back.

I think I also need to get better quality sleep at night!

[Patrick]

Hmmm....

Now that I've quickly tried the Instant Play option, I thought I'd give a quick review of what I think of it. I have mixed feelings...

Yes, it's fast, but it certainly isn't instant. And of course it only plays back on the computer screen, it won't output to a D8 or MiniDV camcorder to be viewed on a NTSC monitor. The audio is fine, but I was really disappointed with the video. It is so strobe-like. I've used Pinnacle Studio Version 7 a lot recently with newbies in our video club, and I'm afraid it's preview quality beats the pants off MSP. Considering the low cost of that Pinnacle program, I'm surprised how much better it's preview quality is. It is instant, and it's very smooth. Many more frames per second than what the Instant Play option of MSP6.5 appears to display. I'm not a hack for Pinnacle, and I still love MSP, but I'm surprised and somewhat disappointed.

Comments?

[Jerry Jones]

???

Well... it sounds like you're just now becoming familiar with the program.

One thing that still puzzles me about your audio commentary is the part about rendering.

Honest... there should be no need to render audio captured from a Pyro as Type 1 using the DV Audio settings.

When I drop any DV clip into the MediaStudio Pro 6.5 timeline, I see both green and red horizontal lines immediately above the timeline...

...these lines mean there's no need to re-render anything.

Now... if I insert a second DV clip on a different track and make part of it overlap with the first, then the green and red lines disappear *above that specific portion where the clips overlap.*

That means rendering *will* be required for that specific portion.

The same is true where titles and filters are concerned...

But if one drops - say - ten clips into the timeline... using cuts-only editing... joining them end to end... then there should be no rendering necessary at all - and no need for the instant playback feature. The green and red horizontal lines should be visible for the duration of the clips.

Cuts-only sequences should preview out to an external monitor in real time... with real time playback... just by clicking on the PREVIEW button.

That's how it's supposed to work.

The Instant Playback feature is useful in previewing portions of the timeline where rendering will occur.

[Patrick]

Jerry, thanks for the info. I did a few tests and I have more to say on the matter, but I've got to get some sleep before I start doing more silly things.

[Patrick]

A few hours later...

Ok, after a few hours sleep I might make more sense now.

Jerry, you are correct when you state that there should not be any rendering necessary when an unadulterated DV clip is played back directly from the timeline. However, in a production there are usually transitions, titles, filters, etc to muck up the process and this is where I find MSP to be slow when rendering the audio. It's the DV audio being rendered during all these transitions, titles, filters, etc that seems to take a long time. I had found with version 6.0 that I could speed up the process by using PCM audio for previews. Maybe that's crazy, but it appeared to work for me. Even if I was only hallucinating, I'm still disappointed that I don't have this same option available to me in 6.5 if I want to use PCM audio for previews when using type 1 DV.

On another related point, is it normal for 48,000 Hz DV audio to sound somewhat distorted when playing back through the sound card from the timeline during preview? I find if it's converted to 32,000 Hz or 44,100 Hz it sounds fine, and at any DV audio setting it sounds fine when going back to the camcorder through the firewire. I'm using a SB AWE64 and I'm wondering if this is common or if there's something wrong with my setup.

[Dr Mordrid]

To give you a point of reference about where you are in terms of DV rendering times;

http://www.hyperactivemusic.com/MS%20Pro%206.0.htm

Just be glad you aren't using Premiere6

Dr. Mordrid

[Joel Cairo]

Patrick:

Regarding the distortion in your 48K audio going through your SB AWE64-- yes, that's "normal", because the card doesn't support 48K sound. I had the same thing happen to me once I started playing with DV files (using the same card), and I didn't know why until I checked the Google archives.

That's why I upgraded to the Turtle Beach Santa Cruz. Now the 48K sound is wonderfully clear as a bell. Everything else sounds great playing through it, too!!

-Joel Cairo

[Patrick]

Doc, I'm familiar with that list as I was one of the first people to contribute data! However, one thing that test did not look at was the time it took to render audio. T'was a shame...

Joel, thanks for the info. I can at least be happy that I'm not imagining the problem now.

[Dr Mordrid]

Ain't that the truth!!

Not to mention that is uses almost unmeasurable resources when playing through DirectSound.

Dr. Mordrid

[wkulecz]

slow audio

Don't know if this helps or not, but I was having long render times when there should be no rendering and audio seemed to be the trouble.

Solution was that somehow RenderAudio=1 got into my Ulead32.ini file!

Changing it to ;RenderAudio which effectively removed it, fixed my problem.

--wally.